So Everyone says that the 84-89 prop valve uses m10x1.0 threads whereas the 89-92 valve converted to m10x1.5 right? Well the prop valve I have here seems to have both, the front ports are coarse but the rear seems to be a fine pitch.. So is the difference between the two valves just on the rear ports?

The reason I ask is I have the following combo.. 92 master, "84-92" SS replacement hard lines and what I think is a pre 89 prop valve.. So here's what fits

Front brakes master to prop
Rear hard lines to prop outlet

What doesn't fit

Front prop outlets to hard lines
Rear master to prop inlet

I was considering just converting to an adjustable prop and have done with it but it seems that the whole bubble/inverted flare thing is a bigger problem than I want to deal with so I plan on ordering a new valve from Ed, just want to make sure that if I order the 89-92 valve, it will bolt right in - don't want to end up with a lighter wallet and the same problem.. Appreciate any input guys.

Thanks,
Richard.

 

Here, Richard, I'm shooting in the dark here. First, I used the first design combination valve in the 1LE swap to my 85 IROC. Zero issues with fitment. That said, I wonder about the SS lines you purchased. You'd think there would be two choices (an 84 to mid-89 and an 89+) instead of a one-size-fits-all. I wonder if the problem lies with the lines.

JamesC

 

Yeah exactly, I didnt realise there was a difference in prop valve fittings until after I had got the new hard lines.

Need to find out definitivley which ports are different, thread wise, between the pre and post 89 prop valves. I dont mind ordering one from Ed, just want to make sure it will work for me before I do.

Thanks,
Richard.

 

Also, I was trying to find the 92 prop valve that I had on the car to compare, but I can only think i turned it in as part of the core when i bought a new booster/master.

 

Picked up a >89 disc/disc prop valve off eBay. Seems like the rear inlet and front outlets got the thread pitch change.. Weird.